1. Technical Field
The present invention relates generally to document imaging and, more particularly, to image rotation with substantially no aliasing error in the resulting image.
2. Background Art
Digital imaging of documents, photographs and other objects provides numerous advantages including the ability to easily process, analyze and communicate images. One common method of creating a digital image is scanning. During scanning, a rectangular window, called an image buffer, which includes the image is typically created. An actual image is then extracted from the image buffer so further data analysis may be conducted on just the image. It is not an infrequent occurrence, however, for the object being scanned to be skewed or angled relative to the image window representation of the image buffer. During the extraction process, it therefore becomes advantageous to rotate the image to attain a properly justified replication.
Present extraction processes are often inadequate for creating accurate replications of images after rotation because the extraction process imposes mistakes in the images. The mistakes, referred to as artifacts, may include such things as broken lines, stepped edges and other abnormalities. One particular type of artifact is referred to as “aliasing error,” and generally includes stepping or breaks in lines of the image. Current correction methods for these mistakes are inadequate, processor intensive and time consuming.
Another challenge faced by users of digital imaging is to balance the desire to retain details in images while minimizing storage space for images. Data compression techniques, for example JPEG, have been developed to increase the ability to retain details, but reduction of data storage remains a problem.
In view of the foregoing, there is a need for a high speed system and method for rotating an image such that the resulting image is substantially free of aliasing errors. It would also be advantageous if this system and method reduced data storage requirements.